This invention relates generally to mechanical joints, and particularly wobble joints wherein one joint member is able to wobble or gyrate about an axis of another joint member through restricted motion of the connection of the joint members.
U.S. Pat. No. 6,115,863 discloses an automatic washing appliance in which a wash plate is supported for wobbling movement within a wash basket for laundering cloths. FIG. 4 of this patent discloses a wobble joint which supports the wash plate for wobbling action during operation of the appliance. The joint is made up in total of at least 11 separate parts which, when assembled, operate to support the outer joint member for relative wobbling movement relative to the inner joint member.
It is an object of the present invention to simplify the manufacture and improve upon the performance of such wobble joints for use in washing appliances and other applications.
A wobble joint constructed according to a presently preferred embodiment of the invention comprises an outer joint member having a curved sliding surface, an inner joint member having a curved sliding surface, and an intermediate joint member disposed between the inner and outer joint members and having an outer curved sliding surface supporting the curved sliding surface of the outer joint member for relative pivotal movement of the outer and intermediate joint members, and an inner curved sliding surface supporting the curved sliding surface of the inner joint member for relative pivotal movement of the inner and intermediate joint members. The joint further includes mutually engaging motion limiting features acting between the intermediate joint member and each of the inner and outer joint members and restricting the relative pivotal movement of the outer and intermediate joint members to pivotal movement in a first plane containing an axis of either the outer or inner joint member which is supported against pivotal movement, and restricting the relative pivotal movement between the intermediate and inner joint members to pivotal movement within a second plane containing the axis and disposed transverse to the first plane. According to the invention, the motion limiting features include first and second arcuate grooves extending parallel to the first and second planes in combination with retainers captured within the grooves and relatively moveable there along to provide the restricted pivoting movement of the joint members.
The invention further contemplates an automatic washing appliance embodying the above-described wobble joint in which a wobble wash plate disposed within a wash basket is supported by the outer joint member for relative wobbling movement about the first joint member during operation of the appliance. The invention has the advantage of simplifying the construction of wobble joints by minimizing the required number of component parts required to support the joint members for relative wobbling movement.
The invention has the further advantage of reducing the cost and simplifying the manufacture of such wobble joints through the formation of curved sliding surfaces and mutually engaging groove and retainer features which eliminate the need to utilize separate pins and bearings to support the joint members as in the prior art described above.
The invention has the further advantage of providing a wobble joint that is more compact in size by eliminating the need to provide a gap or clearance between the joint members that is employed with the prior art joint. The nesting curved sliding surfaces of the joint members places the joint members in contact with one another and thus enables the joint to be made more compactly and with tighter tolerance than that of the known prior art wobble joints.
Another advantage of the present invention is that the tighter tolerance and sliding contact of the joint members reduces lash and thus noise associated with operation of the joint.